心脏脂肪高或可导致糖尿病

旧金山——南佛罗里达大学的Amy C. Alman博士在美国糖尿病学会（ADA）年会报告称，一项针对不同人群的长期队列研究结果显示，大量心周脂肪组织（PAT）与糖尿病发病率较高相关，且独立于全身肥胖因素之外。

研究者指出：“肥胖与心血管疾病和2型糖尿病风险增加相关，特殊部位脂肪堆积可使风险增加更为明显。”

上述结果来自对3,079例CARDIA（年轻成人冠状动脉风险研究）研究受试者第25年检测数据的分析。该试验是1985年在阿拉巴马州、明尼苏达州、伊利诺斯州和加利福尼亚州多个中心开展的一项有关心血管风险和疾病发展的纵向队列研究。

Amy Alman博士

PAT属于异位脂肪组织，包括沉积于心包膜内和冠脉及心旁组织周围的心外膜脂肪组织，分布于心包壁层的表面。研究者通过分析CARDIA研究第25年检测数据，包括在2010~2011年通过胸部CT检测的PAT体积，分析了PAT是否与糖尿病发病率存在正相关。Alman博士解释称，内脏肥胖代谢活跃，与心血管风险的相关性比皮下肥胖更为明显。沉积于体内组织和器官内部及周围的异位脂肪代谢活跃，这些部位包括肝脏、肌肉和心脏周围。

研究者应用多变量逻辑回归模型分析PAT四分位数与糖尿病的相关性。PAT四分位数分别为：<33.5 cm³（第1四分位数/参比体积）、33.5 ~48.7 cm³（第2四分位数）、48.7 ~71.7 cm³（第3四分位数）和>71.7 cm³（第4四分位数）。

3,079例受试者平均年龄51岁，44%为男性，平均体重指数（BMI）为31 kg/m²。其中，419例为糖尿病。PAT体积位于第4四分位数的受试者糖尿病发病率最高，为46%，第1、2和3四分位数受试者分别为12%、18%和 24%。

对肥胖患者PAT体积与糖尿病状态的逻辑回归模型分析表明，校正试验中心、性别、年龄、收缩压、总胆固醇、甘油三酯以及降压和降脂药物治疗后，仅有第4四分位数的PAT体积与糖尿病状态相关[比值比（OR），2.47]。非肥胖患者的情况与之相似(OR, 3.78)。

研究者总结认为：“无论对于肥胖还是非肥胖人群，高比例代谢活跃异位脂肪沉积与糖尿病相关。”

研究者认为，该分析是一项非常有特色的多中心队列研究，受试者为不同种族的中年男性和女性。不过，该研究也存在一些局限性，包括横断面设计，仅检测了一个时间点的PAT，也没有考虑肝脏脂肪等其他异位脂肪组织。研究者计划开展一项针对受试者的纵向分析。

Alman博士无相关利益冲突披露。

爱思唯尔版权所有 未经授权请勿转载

SAN FRANCISCO – A high volume of pericardial adipose tissue was associated with the prevalence of diabetes, independent of overall obesity, results from a long-term, diverse cohort study showed. 

"Obesity is associated with an increased risk for cardiovascular disease and type 2 diabetes, and specific fat deposits may increase the risk more than others," Amy C. Alman, Ph.D., said at the annual scientific sessions of the American Diabetes Association. 

The findings come from an analysis of year-25 exam data among 3,079 participants in CARDIA (Coronary Artery Risk Development in Young Adults), a longitudinal cohort study of the development of cardiovascular risk and disease that began in 1985 and was conducted at centers in Alabama, Minnesota, Illinois, and California.

Visceral adiposity "is metabolically active and more strongly associated with cardiovascular risk than subcutaneous adiposity. Ectopic adipose depots are metabolically active fat found in and around tissues and organs throughout the body, including the liver, muscles, and around the heart," explained Dr. Alman of the department of epidemiology and biostatistics at the University of South Florida, Tampa. 

Pericardial adipose tissue (PAT) is an ectopic fat depot composed of epicardial adipose tissue deep to the pericardium and surrounding the coronary arteries and paracardial tissue, which is located along the surface of the parietal pericardium. She and her associates tested whether PAT was positively associated with prevalent diabetes at the year-25 exam of the CARDIA study. 

Examinations including volume of PAT measures from chest CT scans were performed during 2010-2011, and the researchers used multivariable logistic regression to examine the relation between quartiles of PAT and diabetes. There were four PAT quartiles: less than 33.5 cm³ (quartile 1/referent volume), between 33.5 and less than 48.7 cm³ (quartile 2), between 48.7 and less than 71.7 cm³ (quartile 3), and greater than 71.7 cm³ (quartile 4). 

The mean age of the 3,079 study participants was 51 years, 44% were male, and their average body mass index was 31 kg/m². Of these, 419 had prevalent diabetes. The prevalence of diabetes was highest in the fourth quartile of PAT volume (46% vs. 12% in the first quartile, 18% in the second, and 24% in the third), Dr. Alman reported.

In a logistic regression model of PAT volume on diabetes status by obesity, only PAT volume in the fourth quartile was significantly associated with diabetes status (odds ratio, 2.47), adjusted for field center, gender, age, race, systolic blood pressure, total cholesterol, triglycerides, and treatment with blood pressure– and cholesterol-lowering medications. A similar association was observed among nonobese patients (OR, 3.78). 

"Deposition of a higher proportion of metabolically active ectopic fat is associated with diabetes in both obese and nonobese individuals," Dr. Alman concluded. 

The analysis was "a very well characterized multicenter cohort study with a diverse racial cohort of middle-aged men and women," she added. Limitations of the study, she said, included its cross-sectional design, the fact that PAT was measured at a single point in time, and that it did not account for other ectopic fat depots such as liver fat. A longitudinal analysis of the participants is planned. 

Dr. Alman had no relevant financial conflicts to disclose.